the flipper not flipping

[Encsi Balla]

This is probably going to be the depends-on-the-situation kind of question, but here it is. I just moved to a new area (small town) and started looking for BRRRR deals, made couple offers already but no success yet. One of the seller agents happened to be an active house flipper in the area and told me that he had a house that he had already bought but had no time to flip, since he had other projects going on, therefore he offered to sell it to me - off market. I went to check out the property. The house was completely gutted already, so - very conveniently - all the structural defaults and other blemishes were out in plain site, not behind drywalls. After that I crunched my numbers and got the comps and it looks like a perfect brrrr or flip, whatever I would decide. Asking price 52k, needs about 45k rehab, ARV 120-125k. Sounds perfect, doesn't it?

However, when I started digging deeper I found out that the house flipper owns the house for !10! years. Meanwhile he bought houses that he payed more for than he did for this house, and made less money after flipping than what he would hypothetically make on this deal. So why hasn't he finished this house? Why did he stop after the gut? That just doesn't make sense to me....unless, of course, there is a major issue with the house that made him completely stop after doing the gut. Also since the house is not livable anymore, he can only sell it for a cash buyer, so he kind of cornered himself a little bit. 

Is there any good advice from the community? I am cautious about this situation because of that big red flag, and I would much appreciate the thoughts of more experienced investors!

Thank you very much!